Robust H_∞ Controller Design for Uncertain Neutral Systems via Dynamic Observer Based Output Feedback

In this paper, the dynamic observer-based controller design for a class of neutral systems with H∞ control is considered. An observer-based output feedback is derived for systems with polytopic parameter uncertainties. This controller assures delay-dependent stabilization and H∞ norm bound attenuation from the disturbance input to the controlled output. Numerical examples are provided for illustration and comparison of the proposed conditions.     

Robust Time-varying H∞ Control for Networked Control System with Uncertainties and External Disturbance

In this paper, the robust H∞ control problem is developed for a class of linear time-varying networked control system (NCS) with uncertainties and external disturbance. In network, the network-induced delay and packet dropouts are simultaneously considered. Firstly, a discrete-time switched system model is established based on the signals transmission delay in network. Then, a time-varying H∞ controller is designed. Such the controller can vary according to delay in network. Furthermore, by constructing delay-dependent Lyapunov-Krasovskii functional, a sufficient condition is given to guarantee that the closed-loop system is stochastically stable with an H∞ disturbance attenuation level in terms of nonlinear matrix inequalities. In order to solve the controller gain, the cone complementarity linearization (CCL) algorithm is employed. Finally, a networked DC motor control system is analyzed to illustrate the effectiveness of the proposed method.     

Robust H∞ State-feedback Control for Nonlinear Uncertain Systems with Mixed Time-varying Delays

International Journal of Control, Automation and Systems - This paper presents a new less conservative stability and H∞ state-feedback controller design of nonlinear uncertain systems with...     

Robust H∞ Controller Design for Uncertain Neutral Systems via Dynamic Observer Based Output Feedback

In this paper, the dynamic observer-based controller design for a class of neutral systems with H∞ control is considered. An observer-based output feedback is derived for systems with polytopic parameter uncertainties. This controller assures delay-dependent stabilization and H∞ norm bound attenuation from the disturbance input to the controlled output. Numerical examples are provided for illustration and comparison of the proposed conditions.     

Quantized Sliding Mode H∞ Control for Singular Markovian Jump Systems with Sensor Failure and Randomly Changing Structure

The H_∞ sliding mode control is studied for a class of singular Markovian jump systems with sensor failure, incompleted transition probabilities and randomly changing structure. A quantized input sliding mode controller is designed to deal with the sensor failure and time-varying delay. A new sliding mode surface and a new Lyapunov function are constructed to achieve the system stable and reduce the effect of the jumping mode. Based on the linear matrix inequalities (LMIs) theory, some sufficient conditions are derived to guarantee stochastically admissible with performance γ. The sliding mode reachability is also guaranteed. Simulation results are given to illustrate the effectiveness of the proposed method in this paper.

     

Robust Mixed H2/H∞ Control for An Uncertain Wireless Sensor Network Systems with Time Delay and Packet Loss

In this paper, the problem of robust mixed H₂/H_∞ control is studied for an uncertain wireless sensor network (WSN) systems with random time delay, packet loss and sensor faults. A system model is established based on the characteristics of uncertain time delay and packet loss in WSN. In this model, system uncertainties are represented by random time delay and stochastic packet loss, which are described by a Markov chain. By using a Lyapunov-Krasovskii function, a mode-dependent mixed H₂/H_∞ controller is designed to guarantee both the stochastic stability of the closed-loop system and the prescribed H₂, H_∞ control performances. The sufficient conditions for the existence of the controller are proved by a series of Linear Matrix Inequalities (LMIs). If these LMIs are feasible, the mode-dependent mixed H₂/H_∞ controller can be obtained. Matlab LMI toolbox is used to calculate the control law. Finally, a numerical example and its simulation results demonstrated the effectiveness of the proposed method.

     

H ∞-Control for Guaranteed Simultaneous Input and Output Stability Margins for a Multivariate System

Multivariate controllers guaranteeing a given radius of stability margin both at the physical input and physical output of a system are designed. The problem is reduced to an H -problem of suppression of external perturbations and solved numerically by the MATLAB LMI method.     

Robust H∞ control for stochastic systems with nonlinearity,uncertainty and time-varying delay

This paper deals with the problems of robust stochastic stabilization and $H_{\infty }$ control for uncertain stochastic systems with time-varying delay and nonlinear perturbation. System uncertainties are assumed to be norm bounded and time delay is assumed to be bound and time varying with delay-derivative bounded by a constant, which may be greater than one. First, new delay-dependent criterion is proposed by exploiting delay-partitioned Lyapunov–krasovskii functional and by employing tighter integral equalities to estimate the upper bound of the stochastic differential of Lyapunov–krasovskii functional without ignoring some useful terms. Second, based on the criterion obtained, a delay-dependent criterion for the existence of a state feedback $H_{\infty }$ controller that ensures robust stochastic stability and a prescribed $H_{\infty }$ performance level of the closed-loop system for all admissible uncertainties is proposed. These developed results have advantages over some previous ones, in that they involve fewer matrix variables but have less conservatism and they also enlarge the application scope. New sufficient conditions are presented in terms of linear matrix inequality. Numerical examples are used to illustrate the effectiveness and feasibility of the proposed method.     

Fast Finite-time H∞ Control for a Class of p-normal Form Nonlinear Systems with Output Constraint and Its Application

International Journal of Control, Automation and Systems - In this paper, the fast finite-time H∞, stabilization problem with output constraint is studied for a class of p-normal form...     

A Frequency Condition for the Generalized Recurrent Difference in the Synthesis of H∞-Suboptimal, Decentralized, and Robust Regulators

A new approach to designing control laws under uncertainty produces easily verifiable tests for their generalized recurrent differences and does not require the solution of matrix equations or inequalities. This test is expressed as a frequency inequality, which is verified by verifying whether a polynomial has a real positive root of odd multiplicity. The underlying principles of the method are the necessary and sufficient conditions for a given stabilizing linear feedback to be the local minimax control satisfying the Bellman–Isaac inequality in a differential game with a general quadratic functional. The design of controls for Lur'e systems and systems with uncertain bounded parameters as well as the design of H -suboptimal regulators and decentralized controls for multiconnected systems with unknown cross-coupling are shown to involve a local minimax control problem.     

Simple Robust PID Tuning for Magnetic Levitation Systems Using Model-free Control and $${{\cal H}_\infty}$$ ℋ ∞ Control Strategies

International Journal of Control, Automation and Systems - This paper proposes two control techniques to provide robust tracking for magnetic levitation systems (MLS): model-free control (MFC) and...